Is there a helper extension for AI2?

On a lot of posts that other users posted, I saw some difference to their appearance and other stuff, is there an extension thing that adds functionalities to the AI2 editor?
For example, duplicating components, copy/pasting properties?

Already built-in.

To copy a component, select it in the designer, the use keyboard shortcuts:

CTRL+C then CTRL +V ...should work but currently broken

use this instead

CTRL+INSERT then SHIFT +INSERT

The properties will be copied with the component.

If you just want to copy properties, then easier to set all the properties (where you can) in the blocks editor using anycomponent blocks.

Then are there any other convenient functionalities?

To do what exactly ?

Well, not anything that I want personally, just curious about what other useful functions it has. And there's no other extension for these things?

https://appinventor.mit.edu/explore/library

Okay thanks